The present invention relates to a method for inspecting defects and a device for the same to be used in inspecting and observing fine pattern defects, particles, and the like in production processes, e.g., semiconductor production processes and flat panel display production processes.
An example of a conventional inspection technology relating to the present invention can be found in an inspection device described in pgs. 12–15 of “Clean Technology” (September 1998, Nikkan Kougyou Shuppan, Ltd.).
In this description, non-critical false detentions caused by color discrepancies are prevented from being detected using a floating threshold value algorithm referred to as a segmented auto-threshold algorithm.
This type of conventional technology provides an algorithm for providing threshold values by determining, for individual segments, contrasts and image brightnesses of patterns formed on a specimen. In this algorithm, if pattern contrast or image brightness is high, the threshold value is increased so that inspection sensitivity is decreased. Improving yield in semiconductor production processes requires detecting killer defects at an early stage. With the conventional technology, killer defects may be missed depending on the detected image. Furthermore, with the floating threshold values of the conventional technology, not all false detections may be eliminated depending on color discrepancy conditions.
Also, the conventional technology described above presents three types of inspection devices, and inspection conditions must he created for each of these devices. Generating inspection conditions for each of these devices is time-consuming.
Furthermore, inspection devices need to provide stable sensitivity, but detection sensitivity can vary due to factors such as variations in the light-emission point of the light source of an optical system. As a result, phenomena such as decreased inspection sensitivity over time is possible. Since decreased inspection sensitivity can lead to missed killer defects, monitoring the inspection sensitivity of the device and detecting irregularities quickly can contribute to improved product yield.